When I read the data in the F628 eeprom I get correct minutes seconds and hours but the DoM,dOW,mon,year
data is corrupt. Every time I run that code the calendar data changes to something different and sometimes
some of the data is correct.

When I set alarms they work correctly.

When I replace the PCF8563 with a DS1307 and change the addresses accordingly, the program works perfectly.

I want to use this PCF8563 because it has alarms and battery voltage sensing that the DS1307 doesn't have.

I have also tried 3k3 resistors on SCL & SDA instead of 4k7 but that made no difference.

Re: PCF8563 date data corrupted

Thank you very much Richard , your advice fixed my problem.
I am so happy 'cause I really like this chip.
Now I can apply my mind to getting an interrupt every minute which
appears to be quite cumbersome.